Short for "sovereign citizen", a group of people who believe they do not have to adhere to any laws because they reject the notion they are citizens of a nation and justify it with conspiracy nonsense.
The latter. Everyone believes that they have solved the system, but no one can produce proof. Only increasing degrees of delusion. There are some common items like the UCC and “5-star passports” but after that is fractures into all these supposed loopholes
There are loosely associated groups within them. Some of them are Moorish sovcits, which are loosely associated with the Moorish Science Temple, although they don't like that, and they're all black people who claim to be indigenous to the US. Some of them call themselves secured party creditors, and another big group go by American State Nationals. They're not like an organization, just a bunch of whackadoos who believe the same kind of crazy. I highly recommend looking them up on YouTube because there's a million videos of them getting pulled over, arguing with the cops that they don't have to have a license or insurance because they're travelling not driving and then getting yanked out of their cars and tased. They believe they can pay their bills and they have fake license plates that say Private, and sometimes fake passports.
A special breed of idiot who firmly believes that you can reverse debt by saying "no, you owe me that". They usually do that with a brain-gymnastics interpretation of laws and by adding weird markings to legal documents like invoices. Somehow, taping a coin to an invoice and returning it to the sender somehow pays any debt no matter how high.
They are instructed by so-called gurus, which ironically refuse any alternative form of payment (e.g. said "coin on the invoice") except real dollars.